1. Field of the Invention
The present invention provides a moveable media or paper dam. More specifically, the present invention provides a moveable media dam for a peripheral device which clears media from a feed zone and aligns leading edges of a stack of input media thereby inhibiting multi-sheet feeds.
2. Description of the Related Art
L-path media feed systems have been used for media handling devices such as stand-alone printers and multi-functions devices. In L-path media feed systems, the input media is positioned at the rear of the device in a nearly vertical orientation. The L-path media feed system further comprises a substantially horizontal output tray and a printing zone defined between the input tray and the output tray. The media is moved through a feed path from the near vertical orientation to a substantially horizontal orientation. Thus when viewed from a side, the media moves through a substantially L-shaped path.
However, L-path media feeds have several shortcomings. First, L-path media feed devices have a large height dimension because of the input tray extending upwardly from the peripheral to support input media. Thus, placement of the device on a shelf or cabinet may be difficult. In addition, media loading may also be problematic when the peripheral is placed within the shelf or cabinet because the media generally extends above the input tray. Second, since the media extends above the input tray it is visible to those around the machine, which is generally not aesthetically pleasing to many users. Finally, L-path media feeds are prone to multi-sheet feed problems because of the orientation of the input media. More specifically, the input media is continuously forced downward into a pick area by gravity due to the nearly vertical orientation of the media. As a result of the continuous force on the input media, friction bucklers are utilized to inhibit movement of more than one sheet of media from the input tray to a feed area. However, the friction bucklers may mark and/or bend the media in addition to being an added expense to manufacturers and consumer.
Alternatively, a C-path media feed has also been used in printers and multifunction devices. In general, a C-path media feed utilizes a substantially horizontally disposed input tray adjacent a substantially horizontally disposed output tray and because of this orientation friction bucklers may be removed. Typically, the input tray is positioned beneath the output tray and, as such, is also known as a bottom loading device. The feed path is generally curved from the input tray to the print zone and further to the output tray in order to move the media through a print zone and from a side resembles a substantially C-shaped path. Due to the construction of the C-path media feed, the height of the peripheral or printer is generally decreased because the large upwardly extending media tray used with L-path media feeds is removed. Further, the media is generally hidden from view within the interior of the printer or multi-function device, which is aesthetically pleasing. Finally, with the input tray oriented horizontally, the C-path feed device reduces multi-sheet feed problems due to gravity which are typically associated with L-path media feeds.
Upon changing to a C-path feed system and removing the friction bucklers a further difficulty has arisen. When the friction bucklers are removed, a user may not receive positive feedback that the media is completely inserted into the media tray. Previously such feedback was provided by the bucklers. Without such positive feedback, the user may force the media beyond the rear wall of the input tray and into the feed zone resulting in multi-sheet feeds and media jams. This is highly unacceptable.
Also problematic are multi-sheet feeds of next-to-top sheets caused by friction induced creep. When printing or scanning is performed by a media feed system the media may be continuously fed one sheet after another, starting with an uppermost sheet of the media stack. However, prior art media feeding mechanisms tend to simultaneously feed more than one sheet of the media which is commonly referred to as friction induced creep. The media creep of the next-to-top sheets is generally caused by friction between the uppermost sheet and the next-to-top sheets. Specifically, as the top sheet is picked from an input tray, the next-to-top sheet or sheets, are often partially drawn into the feed mechanism by frictional forces between the top fed sheet and those beneath it. If these next-to-top sheets are not cleared from the feed zone, then multiple sheets may be drawn into the feed zone during a pick cycle resulting in a multi-sheet feed. Multi-sheet feeds are a common problem associated with printers, copiers and other peripheral devices having media feed mechanisms.
Given the foregoing, it will be appreciated that an apparatus is needed which provides a user with positive feedback that a media stack is fully inserted into a media tray. It is further appreciated that a device is needed which aligns the leading edges of the media stack between sheets feeds to negate the effects of media creep and thereby inhibit multi-sheet feeds.